Thermal resistance information ST6710

[WEmme]

Hello,

I need some information on the thermal resistance Rthja and Rthjc of the STM6710 (package SOT23-6L). Could you please send some technical information like a datasheet which we can forward to certification authority?

I often miss this information in STM's datasheets. I searched the community posts and detected that other users also miss it many times for many types of components. Is there a reason why it is not published in the datasheets together with other important data? 

Thank you in advance!

Best regards

Wolfgang

[Peter BENSCH]

If you estimate the maximum power dissipation of devices such as the STM6710 (absolute max output current 20mA multiplied by the assumed RESET low voltage 0.8V = ~16mW), this power would lead to a temperature difference of 4.8 Kelvin at a (very poor) thermal resistance of 300K/W. However, common devices in SOT23-6 tend to have thermal resistances of 50...100K/W, i.e. a factor of 3...6 better.

In a realistic scenario, in which 1.2mA leads to a power loss of max. 0.48mW, the temperature increase is negligible at significantly less than 1K.

If this statement is not sufficient for you, you are welcome to contact online support OLS with a personal ticket with reference to this thread (just copy the URL).

Hope that helps?

Regards
/Peter

[WEmme]

Hi Peter,

I really appreciate this engineering judgement and I guess that it will be the right assumption. I believe that this will be right and honestly this would be my favorite way to judge about the topic for myself.

But certification authorities are not electronic engineers and want to get some written statement like a manufacturer's datasheet or alike including a hard value. So I will need to have some manufacturer's value which can be read in some manufacturer's declaration or publication.

I guess STMicro has to have some table for several packages like SOT23-6L where the values of the RThs have to be drawn from. Normally it would be ok of the standard JEDEC value would be placed, but I need it anywhere written officially where the auditor can crossceck. Sorry for inconvenience but I don't want to throw the component out of the design because of that issue.

I don't understand why STM doesn't give a hint where to find these values, other semiconductor companies sometimes do so. It should be no secret at all...

Thanks and regards

Wolfgang